1. Field of the Invention
The present invention relates to communicating voice data over a packet-switched or circuit-switched network with a telephone set for use by a human; and, in particular relates to providing a voice instant messaging (VIM) service on a programmable telephone set.
2. Description of the Related Art
Networks of communications devices, general-purpose computer systems and specific purpose devices connected by external communication links are well known and widely used in commerce. The networks often include one or more network devices that facilitate the passage of information between end stations, such as telephones and general purpose computing devices, which originate or receive the information. A network node is a network device or end station connected by the communication links. Information is exchanged between network nodes in discrete data packets according to one or more of many well known, new or still developing protocols. In this context, a protocol consists of a set of rules defining how the nodes interact with each other based on information sent over the communication links. The protocols are effective at different layers of operation within each network node, from generating and receiving physical signals of various types, to selecting a link for transferring those signals, to the format of information indicated by those signals, to identifying which software application executing on a computer system sends or receives the information. Signaling between nodes is typically effected by exchanging special data packets called control plane data packets. Each data packet typically comprises 1] header information associated with a particular protocol, and 2] payload information that follows the header information and contains information that may be processed independently of that particular protocol. Often, the data in the payload for the particular protocol includes a header and payload for a different protocol associated with a different, usually higher layer protocol. The payload protocol is said to be encapsulated in the header protocol.
Commercial services that provide voice data communicated over a packet-switched network predominately use the Internet Protocol (IP) as the internetworking layer protocol to communicate with devices on different networks. A voice data session over IP between end stations is set up predominately using IP datagrams that include in the IP payload the Session Initiation Protocol (SIP) header and payload. The SIP header provides information about the party that originated the voice data, e.g., a caller network identifier (“caller ID”) and the called party, e.g., a target network identifier (“target ID”).
Many telephone sets, including wireless mobile telephone sets and computers so configured, include one or more speakers for presenting audio data, microphones for collecting audio data and displays for presenting visual data. Some include visual recorders, such as digital cameras and video recorders. On programmable telephone sets, functions of at least some of these elements can be controlled by instructions, called software, that can be changed without a change in equipment. The software is executed by processor either on the telephone set itself or on a remote host in communication with the telephone set either directly or indirectly through a network. For various telephone sets, the software provides services such as call forwarding and voice mail and text messaging.
Many services are known using communication networks. A popular service is instant messaging (IM), whereby a server connected to a computer via a network detects when the computer is active and allows other users on the network to send text to the computer when the computer is active. When text is delivered to the active computer, the computer displays the text instantly in at least a portion of a visual display screen. The IM service, however, does not include both instant audio play of voice or other audio data generated in real time and persistence. Furthermore, IM requires a computer or similar device and a display with sufficient display area for a substantial amount of text. Although a computer with at least one speaker and one microphone linked to a network can be programmed to operate as a telephone set, in general, computers are more expensive and less available than telephone sets that do not do general purpose computing.
Voicemail is a service whereby one sender uses a telephone set to record an audio message directed to a particular recipient. The sender must dial the recipient, listen to a message that the recipient is not available and wait for a prompt to begin recording. The recorded audio message lies dormant until the recipient decides to retrieve and listen to the message, typically using another telephone set. One shortcoming of voicemail is the requirement to wait for a prompt before the audio content can be recorded. Another shortcoming of voicemail is that id does not provide instant presentation of the audio data. The content can become stale or obsolete before the listener plays the message.
An intercom is a service by which one button on one telephone set activates speakers on several telephone sets. However, an audio message sent in real time over the intercom service is transient and does not persist to be replayed in case the intended recipient is not in the vicinity of the telephone set speaker, or did not understand the audio message completely.
Based on the foregoing, there is clear need for techniques that allow instant audio messaging for voice and other real-time audio data, which do not suffer the disadvantages of prior art approaches.